This invention relates to liquid crystal display cells in general and more particularly to smectic LCD's having a roughened electrically insulating surface layer covering the electrodes of the cell.
It has been found that the switching threshold voltage of a smectic liquid crystal dynamic scattering display cell filled with a positive dielectric anisotropy smectic material, such as for instance 4-n-octyl-4'-cyano biphenyl, is dependent upon the surface texture of the electrodes or any insulating layer covering the electrodes. In particular it has been found that when the electrodes of such a cell are covered with a chemical vapor reaction deposited insulating layer, such as a silica layer deposited by reacting silane with oxygen, the smooth surface of the deposited layer provides a particularly high threshold.